Does anyone know of a way to communicate with the server during an
onchange or onblur event?

I am trying to emulate the functionality of a client/server application
where, when a user leaves a field, datbase validation immediately
occurs.

Are there components which will do this? Preferably gnu license with
source.

What about a minimized window which submits itself and accesses the
data? How do I get the results back to the parent window synchronously?